"mark" wrote in message
et...

I've to connect a 110mm soil pipe to an existing 4" clay sewer pipe. It
will be near enough at a right angle.

Depth will be about 750mm-900mm.


To make it roddable I will need an inspection chamber.
There is obviously a relationship between the diameter of inspection
chamber
and depth to permit the use of rods.
I'm keen to install the smallest I can get away with as they are not cheap
things.
Advice please.

mark


It's easier to dig down and build a brickwork chamber with a lid. Make the
chamber suit the lid you buy. A good lid is 3 foot X 2 Foot for a rodding
access chamber, making the longest face toward the direction of rod pull.

The chamber depth will be determined by the depth of the drain you are
connecting up with, and a couple of inches below for the chamber sole plate.